The PTP, STEP, Regulates Amphetamine Actions

PTP、STEP 规范安非他明行为

• 批准号: 6917938
• 负责人: Paul J Lombroso
• 金额: $ 32.7万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-15 至 2009-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6917938
• 关键词: JUN kinase; amphetamines; amygdala; behavioral /social science research tag; behavioral habituation /sensitization; biological signal transduction; corpus striatum; dopamine; fos protein; frontal lobe /cortex; gene expression; genetic regulation; genetically modified animals; glutamates; immunocytochemistry; laboratory mouse; laboratory rabbit; laboratory rat; mitogen activated protein kinase; nucleus accumbens; phosphorylation; protein binding; protein tyrosine phosphatase; western blottings

DESCRIPTION (provided by applicant): Chronic intermittent exposure to stimulant drugs produces persistent and progressive changes in behavior including responses to subsequent drug challenges. This phenomenon is termed sensitization. Although animal models have provided information with regard to the initial biochemical changes involved in sensitazation, less is known about subsequent steps. The present RO1 will investigate this question. Our laboratory has discovered a family of protein tyrosine phosphatases (PTPs) that are expressed within neurons of the CNS. This PTP, termed STEP, is highly enriched in the striatum, nucleus accumbens, amygdala, and the frontal cortices. We recently determined that STEP regulates the activity of the MAP kinase members, ERKI/2. STEP is itself regulated by dopamine and glutamate signaling. Dopamine stimulation leads to the phosphorylation of key regulatory residues and inactivates STEP. Glutamate signaling dephosphorylates and activates STEP. STEP thus acts as a switch that regulates the activity ERK1/2 and limits its ability to activate downstream substrates. We propose that STEP regulates the effects of amphetamine. It does so by controlling the activity of ERKI/2. Consistent with this hypothesis, preliminary data in rats demonstrate that STEP is phosphorylated after amphetamine treatment. The sites phosphorylated are key regulatory residues in a domain required for binding to the ERKs. When STEP is phosphorylated at that site, the ERK signaling cascade is sustained. We will conduct time-course and dose-response analyses with psychostimulants, and perform immunocytochemical and Western blot analyses to determine the patterns of p-ERK, p-STEP, p-CREB, p- Elk-1 and the immediate early genes c-fos, jun and AfosB. We propose that the duration that ERKI/2 remain active determines the pattern of gene expression. Functional studies will disrupt the ability of STEP binding to ERK or disrupt the ability of STEP to let go of ERK. This will be tested by using TAT-peptide technology that introduces protein sequences that either prevent STEP from binding to ERK or never let go of ERK. We show preliminary feasibility data on this approach. A complementary set of experiments will study the STEP knock-out mouse that we predict is hypersensitive to stimulant treatment.

描述（由申请人提供）：慢性间歇性暴露于兴奋剂药物会导致行为发生持续性和进行性变化，包括对后续药物激发的反应。这种现象被称为敏化。虽然动物模型提供了关于敏化作用的初始生化变化的信息，但对后续步骤知之甚少。 目前的RO 1将调查这个问题。我们的实验室已经发现了一个蛋白酪氨酸磷酸酶（PTPs）家族，在中枢神经系统的神经元内表达。这种PTP被称为STEP，在纹状体、伏隔核、杏仁核和额叶皮质中高度富集。我们最近确定STEP调节MAP激酶成员ERKI/2的活性。STEP本身由多巴胺和谷氨酸信号调节。多巴胺刺激导致关键调节残基的磷酸化并使STEP失活。谷氨酸信号去磷酸化并激活STEP。因此，STEP作为一个开关，调节ERK 1/2的活性，并限制其激活下游底物的能力。 我们建议STEP调节安非他明的作用。它通过控制ERKI/2的活性来实现。与这一假设相一致，大鼠的初步数据表明，STEP是安非他明治疗后磷酸化。磷酸化的位点是与ERK结合所需的结构域中的关键调节残基。当STEP在该位点磷酸化时，ERK信号级联反应得以维持。我们将对精神兴奋剂进行时间过程和剂量反应分析，并进行免疫细胞化学和蛋白质印迹分析，以确定p-ERK，p-STEP，p-CREB，p-Elk-1和立即早期基因c-fos，jun和AfosB的模式。我们认为ERKI/2保持活性的持续时间决定了基因表达的模式。功能研究将破坏STEP与ERK结合的能力或破坏STEP释放ERK的能力。 这将通过使用TAT肽技术进行测试，该技术引入蛋白质序列，要么阻止STEP与ERK结合，要么永远不会释放ERK。我们展示了这种方法的初步可行性数据。一组互补的实验将研究STEP基因敲除小鼠，我们预测它对兴奋剂治疗过敏。